The Most Important Vitamin in Pregnancy? Vitamin D?

April 23, 2018

Could this be the Most Important Vitamin in Pregnancy?

Trying to conceive or are currently pregnant?
It’s important to get your Vitamin D levels tested.

What is Vitamin D?

Vitamin D in it’s active form is actually a hormone. And like many hormones, appropriate levels are necessary for you to function at your best.

We obtain only a small amount of vitamin D from our food. 90% of our vitamin D is synthesized in the skin from sunlight exposure – specifically from UVB absorption. Living in a country of northern latitude means that, for at least 6 months out of the year, we are unable to produce adequate amounts of vitamin D (1).

A staggering 50% of the world is vitamin D deficient, and this deficiency is attributed to season, latitude, and time spent indoors (2).

Vitamin D deficiency has been associated with all kinds of individual risk factors, like cardiovascular disease, osteoporosis, type 2 diabetes, infertility, and an increased susceptibility to the cold and flu, but are there any potential risks to offspring if a woman is deficient while pregnant?

Health Outcomes to Baby

The vitamin D status of a developing baby depends exclusively on his or her mother’s supply, therefore, low maternal vitamin D concentrations are of concern in pregnancy.

New research from the University of Southern California adds to an increasing body of evidence that low maternal vitamin D status has consequences to the developing baby.

The study found that low maternal vitamin D status in pregnancy could pre-program babies to become obese children and adults (3). In this study, 6-year-olds born to mothers with very low vitamin D levels during their first trimester had larger waists and more body fat. This is likely due to vitamin D’s established role on adipocyte (fat cell) formation, and may exert an in utero programming effect on offspring adiposity.

Vitamin D deficiency in pregnancy has increased dramatically within the last 2 decades.   About 66 percent of the pregnant women in the study were deficient in vitamin D in the first trimester, a time when all major systems and organs begin to form.

Vitamin D insufficiency has also been associated with an increased risk of childhood eczema and type 1 diabetes (4).

Health Outcomes during Pregnancy

There may also be a relationship between vitamin D deficiency and an increased risk of pre-eclampsia (5). Pre-eclampsia is the onset of high blood pressure in pregnancy after week 20, in women whose blood pressure had been previously normal, along with other symptoms of organ damage.

The cause of pre-eclampsia is not yet fully understood, however, research suggests that the up-regulation of inflammatory mediators produced by the placenta is involved in the process (6). Vitamin D is known to have anti-inflammatory properties and may be an important factor in reducing this risk.

Low vitamin D levels have also been associated with pre-term labour (7). Deficiency could also increase the risk of gestational diabetes and vitamin D supplementation may play a role in prevention (8, 9).

5 signs you might be deficient in Vitamin D

Many people with a vitamin D deficiency may have no symptoms or go many years without experiencing symptoms. Therefore, it’s dangerous to rely on symptoms alone to determine a deficiency.

However, some symptoms that could indicate a vitamin D deficiency include:

  1. Getting the cold or flu frequently
  2. Exhaustion, even with enough sleep
  3. Feeling down; lacking motivation
  4. Aches and pains in muscles, bones and joints
  5. Unexplained infertility

Next Steps

If you’re trying to conceive, or are currently pregnant, speak to your Naturopathic Doctor (ND) about getting your vitamin D levels tested. This simple blood test provides a numerical value that allows your ND to determine if your levels are within the sufficient range.

Canadians are usually deficient in vitamin D due to our long winter months. It’s especially important for women who are pregnant, or who are trying to conceive, to have their vitamin D levels tested to avoid labour complications, as well as to improve health outcomes for both baby and mom.

Low vitamin D levels can be corrected with supplementation, however, it’s important to work with a knowledgable health care provider who can safely prescribe and monitor the appropriate dose to achieve sufficiency. This is because overdosing is possible, and can lead to toxicity. The only way to know the appropriate dose is through laboratory testing.

Prenatal care is a passion of mine, and has been a clinical focus of mine during my fourth year internship. I’m currently an intern on the fertility focus shift at the Robert Schad Naturopathic College, where I help couples achieve a healthy pregnancy and carry that pregnancy to term. If you’re ready to start planning a family, let’s work together to optimize your fertility. 

  1. Wacker, M. and Holick, M. (2013). Sunlight and Vitamin D. Dermato-Endocrinology, 5(1), pp.51-108.
  2. Nair, R. and Maseeh, A. (2012). Vitamin D: The “sunshine” vitamin. J Pharmacol Pharmacother, 3(2), pp.118-126.
  3. Daraki, V. et al. (2018). Low maternal vitamin D status in pregnancy increases the risk of childhood obesity. Pediatric Obesity.
  4. Vandevijvere, S., Amsalkhir, S., Van Oyen, H., Moreno-Reyes R. High Prevalence of Vitamin D Deficiency in Pregnant Women: A National Cross-Sectional Survey. (2012). Plos ONE, 7(8).
  5. Tabesh, M., Salehi-Abargouie, A., Esmaillzadeh, A. Maternal Vitamin D Status and Risk of Pre-Eclampsia: A Systematic Review and Meta-Analysis. The Journal of Clinical Endocrinology & Metabolism. 2013;98(8):3165-3173.
  6. Purswani, J., Gala, P., Dwarkanath, P., Larkin, H., Kurpad, A. and Mehta, S. (2017). The role of vitamin D in pre-eclampsia: a systematic review. BMC Pregnancy and Childbirth, 17(1).
  7. Amegah, A., Klevor, M., & Wagner, C. (2017). Maternal vitamin D insufficiency and risk of adverse pregnancy and birth outcomes: A systematic review and meta-analysis of longitudinal studies. PLOS ONE, 12(3).
  8. Zhang, Y., Gong, Y., Xue, H., Xiong, J. and Cheng, G. (2018). Vitamin D and gestational diabetes mellitus: a systematic review based on data free of Hawthorne effect. BJOG: An International Journal of Obstetrics & Gynaecology.
  9. Shahgheibi, S., Farhadifar, F., Pouya, B. (2016). The effect of vitamin D supplementation on gestational diabetes in high-risk women: Results from a randomized placebo-controlled trial. Journal of Research in Medical Sciences, 21(1), p.2.

Farah Mejren is in her fourth year of Naturopathic Medical school, completing her Naturopathic Medical Internship at the Canadian College of Naturopathic Medicine. She holds a Bachelors of Science Degree in Psychology, with a focus on behavioural neuroscience, from the University of British Columbia.

Farah is completing part of her Naturopathic internship at the Integrative Health as well as at the Brampton Civic Hospital. She is also a Clinical Intern on the Fertility and Reproductive Health Focus shift at CCNM, where she receives additional training in complimentary fertility care.

Farah has a special interest in endocrinology and hormone balance, digestive health, and skin care. She understands how each system influences the other, and is passionate about identifying the root cause of health concerns

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